RTFA: http://www.technologyreview.com/Infotech/20463/

To prevent rain over the roofless 91,000-seat Olympic stadium that Beijing natives have nicknamed the Birds Nest, the citys branch of the national Weather Modification Office–itself a department of the larger China Meteorological Administration–has prepared a three-stage program for the 2008 Olympics this August.

First, Beijings Weather Modification Office will track the regions weather via satellites, planes, radar, and an IBM p575 supercomputer, purchased from Big Blue last year, that executes 9.8 trillion floating point operations per second. It models an area of 44,000 square kilometers 17,000 square miles accurately enough to generate hourly forecasts for each kilometer.

Then, using their two aircraft and an array of twenty artillery and rocket-launch sites around Beijing, the citys weather engineers will shoot and spray silver iodide and dry ice into incoming clouds that are still far enough away that their rain can be flushed out before they reach the stadium.

Finally, any rain-heavy clouds that near the Birds Nest will be seeded with chemicals to shrink droplets so that rain wont fall until those clouds have passed over. Zhang Qian, head of Beijings Weather Modification Office, explains, “We use a coolant made from liquid nitrogen to increase the number of droplets while decreasing their average size. As a result, the smaller droplets are less likely to fall, and precipitation can be reduced.” August is part of Northeast Asias rainy season; chances of precipitation over Beijing on any day that month will approach 50 percent. Still, while tests with clouds bearing heavy rain loads havent always been successful, Qian claims that “the results with light rain have been satisfactory.”

This entry was posted by fumf at 2008/03/27/1022 and is filed under weather control. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.